<template>
  <div class="q-pa-md">
    <q-table
      style="height: 400px"
      flat bordered
      ref="tableRef"
      title="Treats"
      :rows="rows"
      :columns="columns"
      :table-colspan="9"
      row-key="index"
      virtual-scroll
      :virtual-scroll-item-size="48"
      :pagination="pagination"
      :rows-per-page-options="[0]"
      v-model:expanded="expanded"
    >

      <template v-slot:header="props">
        <q-tr :props="props">
          <q-th auto-width />

          <q-th
            v-for="col in props.cols"
            :key="col.name"
            :props="props"
          >
            {{ col.label }}
          </q-th>
        </q-tr>
      </template>

      <template v-slot:body="props">
        <q-tr :props="props" :key="`m_${props.row.index}`">
          <q-td auto-width>
            <q-toggle v-model="props.expand" checked-icon="add" unchecked-icon="remove" :label="`Index: ${props.row.index}`" />
          </q-td>

          <q-td
            v-for="col in props.cols"
            :key="col.name"
            :props="props"
          >
            {{ col.value }}
          </q-td>
        </q-tr>
        <q-tr v-show="props.expand" :props="props" :key="`e_${props.row.index}`" class="q-virtual-scroll--with-prev">
          <q-td colspan="100%">
            <div class="text-left">This is expand slot for row above: {{ props.row.name }} (Index: {{ props.row.index }}).</div>
          </q-td>
        </q-tr>
      </template>

    </q-table>
  </div>
</template>

<script>
import { ref, onMounted } from 'vue'

const columns = [
  {
    name: 'desc',
    required: true,
    label: 'Dessert (100g serving)',
    align: 'left',
    field: row => row.name,
    format: val => `${val}`,
    sortable: true
  },
  { name: 'calories', align: 'center', label: 'Calories', field: 'calories', sortable: true },
  { name: 'fat', label: 'Fat (g)', field: 'fat', sortable: true, style: 'width: 10px' },
  { name: 'carbs', label: 'Carbs (g)', field: 'carbs' },
  { name: 'protein', label: 'Protein (g)', field: 'protein' },
  { name: 'sodium', label: 'Sodium (mg)', field: 'sodium' },
  { name: 'calcium', label: 'Calcium (%)', field: 'calcium', sortable: true, sort: (a, b) => parseInt(a, 10) - parseInt(b, 10) },
  { name: 'iron', label: 'Iron (%)', field: 'iron', sortable: true, sort: (a, b) => parseInt(a, 10) - parseInt(b, 10) }
]

const seed = [
  {
    name: 'Frozen Yogurt',
    calories: 159,
    fat: 6.0,
    carbs: 24,
    protein: 4.0,
    sodium: 87,
    calcium: '14%',
    iron: '1%'
  },
  {
    name: 'Ice cream sandwich',
    calories: 237,
    fat: 9.0,
    carbs: 37,
    protein: 4.3,
    sodium: 129,
    calcium: '8%',
    iron: '1%'
  },
  {
    name: 'Eclair',
    calories: 262,
    fat: 16.0,
    carbs: 23,
    protein: 6.0,
    sodium: 337,
    calcium: '6%',
    iron: '7%'
  },
  {
    name: 'Cupcake',
    calories: 305,
    fat: 3.7,
    carbs: 67,
    protein: 4.3,
    sodium: 413,
    calcium: '3%',
    iron: '8%'
  },
  {
    name: 'Gingerbread',
    calories: 356,
    fat: 16.0,
    carbs: 49,
    protein: 3.9,
    sodium: 327,
    calcium: '7%',
    iron: '16%'
  },
  {
    name: 'Jelly bean',
    calories: 375,
    fat: 0.0,
    carbs: 94,
    protein: 0.0,
    sodium: 50,
    calcium: '0%',
    iron: '0%'
  },
  {
    name: 'Lollipop',
    calories: 392,
    fat: 0.2,
    carbs: 98,
    protein: 0,
    sodium: 38,
    calcium: '0%',
    iron: '2%'
  },
  {
    name: 'Honeycomb',
    calories: 408,
    fat: 3.2,
    carbs: 87,
    protein: 6.5,
    sodium: 562,
    calcium: '0%',
    iron: '45%'
  },
  {
    name: 'Donut',
    calories: 452,
    fat: 25.0,
    carbs: 51,
    protein: 4.9,
    sodium: 326,
    calcium: '2%',
    iron: '22%'
  },
  {
    name: 'KitKat',
    calories: 518,
    fat: 26.0,
    carbs: 65,
    protein: 7,
    sodium: 54,
    calcium: '12%',
    iron: '6%'
  }
]

const seedSize = seed.length

let rows = []
for (let i = 0; i < 1000; i++) {
  rows = rows.concat(seed.map((r, j) => ({ ...r, index: i * seedSize + j + 1 })))
}

const initialExpanded = rows.filter((r, i) => i % 3 === 0).map(r => r.index)

export default {
  setup () {
    const tableRef = ref(null)

    onMounted(() => {
      tableRef.value.scrollTo(5000)
    })

    return {
      tableRef,

      expanded: ref(initialExpanded),
      columns,
      rows,

      pagination: {
        rowsPerPage: 0
      }
    }
  }
}
</script>
